Can be one of the following: "webdav" - In this case the source is a WebDAV path."caldav" - In this case the source is a CalDAV path."url" - In this case the source is a URL.
"webdav" - In this case the source is a WebDAV path.
"caldav" - In this case the source is a CalDAV path.
"url" - In this case the source is a URL.